Field of the Invention
The present description relates to a clamping collar comprising a belt looped back onto itself around a substantially cylindrical outline and having two ends provided with lugs that are upstanding relative to said outline and that are suitable for being brought closer together for tightening the collar, the collar further comprising a spacer having a land extending substantially along said outline between the ends of the belt and a web comprising at least a first tab that is upstanding relative to said land, which web extends between the lugs.
The land of the spacer serves to bridge the gap between the ends of the belt, in order to ensure that the collar bears almost continuously around the article it is clamping, in particular when said article is a pipe clamped onto a tube through which a fluid flows, in order to ensure that the clamping is leaktight, for example.
Description of Related Art
A collar of this type is known from Document U.S. Pat. No. 7,055,223. In that collar, the lugs are provided with holes through which the shank of a tightening bolt passes, the head of which bolt is retained behind one of the two lugs, while a nut is retained behind the other lug. In radial section, i.e. perpendicularly to the axis of the cylindrical outline, the web of that spacer is V-shaped, the ends of the branches of the V-shape bearing against respective ones of the inside faces of the lug in a region remote from the axis. The land is made up of land portions, that are cut out from the branches of the V-shape. Insofar as those branches are also provided with holes through which the tightening shank can pass, those land portions are cut out in zones of the spacer that extend between said holes and the side ends of the spacer. Thus, the land portions are of small width, as measured parallel to the axis of the substantially cylindrical outline, said width being very significantly less than the total width of the spacer. Specifically, said land portions are thin cut-out strands, and their contact surface areas over which they are in contact with the article to be clamped by the collar are small. In theory, the land of the spacer serves to procure continuous contact with the article that is to be clamped, by bridging the gap situated between the ends of the belt. However, as indicated above, the land of that prior art is actually made up of a plurality of land portions in the form of thin strands having small surface areas of contact with said article.
As a result, the bearing continuity is not certain because a large fraction of the surface area of the article that is situated between the ends of the belt is not covered by the strands. In addition, said strands themselves lack strength and might deform under the effect of large tightening forces.
It is also known, e.g. from Document WO 2011/011773 that a spacer can be formed by a solid block disposed between the lugs. That spacer is relatively expensive to manufacture, and it has a relatively large weight and very high stiffness, so that its shape does not adapt to accommodate the reduction in the diameter of the belt that takes place during tightening.